METHOD OF VECTOR PRIVATE CONTROL OF ASYNCHRONOUS ELECTRIC DRIVE

Анализируется проблематика векторного частотного управления асинхронным электроприводом, широко применяемым в качестве исполнительного элемента в рамках современных средств построения обрабатывающих комплексов, разрабатываемых в машиностроительной отрасли. Предлагается вариант частотно-регулируемого асинхронного электропривода, управляемыми величинами которого являются полярные координаты вектора тока в обмотке статора. В данном варианте применяется закон управления, согласно которому угол между векторами тока в обмотке статора и потокосцеплением обмотки ротора не меняется. Управление скоростью вращения электропривода и электромагнитным моментом реализуется заданием модуля тока обмотки статора. При этом формирование угла поворота вектора тока обмотки статора, зависящего от модуля величины потокосцепления роторной обмотки и значения скольжения асинхронного двигателя, дает возможность сохранять постоянным угол между векторами тока обмотки статора и потокосцеплением обмотки ротора, что, в свою очередь, реализует направленное формирование переходных процессов в асинхронном двигателе. Рассматриваемый вариант частотно-регулируемого асинхронного электропривода может найти применение в производственных механизмах, в которых быстродействие не является определяющим критерием функционирования привода, а важно плавное регулирование электромагнитного момента и возможность его ограничения во всех режимах работы. Данный способ управления характеризуется тем, что электромагнитный момент определяется исключительно модулем тока обмотки статора, а контур регулирования скольжения используется для реализации закона поддерживания постоянства угла между током обмотки статора и потокосцеплением обмотки ротора The article analyzes the problems of vector frequency control of asynchronous electric drive, widely used as an executive element in the framework of modern means of constructing processing complexes developed in the machine-building industry. Here we propose a variant of a frequency-controlled asynchronous electric drive, in which the polar coordinates of the current vector in the stator winding are the controlled quantities. In this variant, the control law is applied, according to which the angle between the current vectors in the stator winding and the flow coupling of the rotor winding does not change. The control of the speed of rotation of the electric drive and the electromagnetic torque is realized by setting the current module of the stator winding. At the same time, the formation of the angle of rotation of the current vector of the stator winding, depending on the modulus of the magnitude of the flow coupling of the rotor coil and the sliding value of the asynchronous motor, makes it possible to keep the angle between the current vectors of the stator winding and the flow coupling of the rotor winding constant, which in turn implements the directional formation of transients in the asynchronous motor. The considered variant of a frequency-controlled asynchronous electric drive can be used in production mechanisms in which speed is not a determining criterion for the operation of the drive, but smooth regulation of the electromagnetic torque and the possibility of its limitation in all operating modes is important. This control method is characterized by the fact that the electromagnetic moment is determined exclusively by the current module of the stator winding, and the slip control circuit is used to implement the law of maintaining the constancy of the angle between the current of the stator winding by the flow coupling of the rotor winding

Walking Robot for Moving on Vertical and Arbitrarily Oriented Surfaces

The article deals with the design of a walking robot with gripping devices that allow the robot to move on arbitrarily oriented surfaces in space. Such robots are relevant primarily for the inspection of various industrial structures. A model of a two-support robot with gripping devices that allow it to be attached to support surfaces with a small curvature, but arbitrarily oriented in space, is proposed. To ensure attachment to the support surfaces, the robot is designed with five degrees of freedom. An important criterion is the possibility of dexterous movement on surfaces. One of the degrees of freedom of the robot was made linear, which makes it easier to step over obstacles and allows you to implement simpler walking algorithms. When the robot is attached to the supporting surfaces by two gripping devices at once, the kinematic chain is closed. This can lead to an increase in forces and moments in the robot’s links. In this paper, it is applied to use two methods of controlling the drives of the links together – the implementation of impedance control by introducing feedback on the evaluation of the moment based on the motor currents and ensuring the pliability of the gripping devices due to its own elasticity. A mathematical simulation of the robot was carried out, which showed the possibility of reducing the forces in the robot links when attaching the robot to two support surfaces at the same time. The best results were achieved when controlling the current vector of a synchronous motor and using current signals to implement impedance control.

Additional evidence on the efficacy of different Akirin vaccines assessed on Anopheles arabiensis (Diptera: Culicidae)

Background Anopheles arabiensis is an opportunistic malaria vector that rests and feeds outdoors, circumventing current indoor vector control methods. Furthermore, this vector will readily feed on both animals and humans. Targeting this vector while feeding on animals can provide an additional intervention for the current vector control activities. Previous results have displayed the efficacy of using Subolesin/Akirin ortholog vaccines for the control of multiple ectoparasite infestations. This made Akirin a potential antigen for vaccine development against An. arabiensis. Methods The efficacy of three antigens, namely recombinant Akirin from An. arabiensis, recombinant Akirin from Aedes albopictus, and recombinant Q38 (Akirin/Subolesin chimera) were evaluated as novel interventions for An. arabiensis vector control. Immunisation trials were conducted based on the concept that mosquitoes feeding on vaccinated balb/c mice would ingest antibodies specific to the target antigen. The antibodies would interact with the target antigen in the arthropod vector, subsequently disrupting its function. Results All three antigens successfully reduced An. arabiensis survival and reproductive capacities, with a vaccine efficacy of 68–73%. Conclusions These results were the first to show that hosts vaccinated with recombinant Akirin vaccines could develop a protective response against this outdoor malaria transmission vector, thus providing a step towards the development of a novel intervention for An. arabiensis vector control. Graphic Abstract

Towards a Sustainable Vector-Control Strategy in the Post Kala-Azar Elimination Era

Visceral leishmaniasis (VL) is a potentially deadly parasitic disease. In the Indian sub-continent, VL is caused by Leishmania donovani and transmitted via the bite of an infected Phlebotomus argentipes female sand fly, the only competent vector species in the region. The highest disease burden is in the northern part of the Indian sub-continent, especially in the state of Bihar. India, Bangladesh, and Nepal embarked on an initiative, coordinated by World Health Organization, to eliminate VL as a public health problem by the year 2020. The main goal is to reduce VL incidence below one case per 10,000 people through early case-detection, prompt diagnosis and treatment, and reduction of transmission using vector control measures. Indoor residual spraying, a major pillar of the elimination program, is the only vector control strategy used by the government of India. Though India is close to its VL elimination target, important aspects of vector bionomics and sand fly transmission dynamics are yet to be determined. To achieve sustained elimination and to prevent a resurgence of VL, knowledge gaps in vector biology and behavior, and the constraints they may pose to current vector control methods, need to be addressed. Herein, we discuss the successes and failures of previous and current vector-control strategies implemented to combat kala-azar in Bihar, India, and identify gaps in our understanding of vector transmission towards development of innovative tools to ensure sustained vector control in the post-elimination period.